DE102013217402A1 - SYSTEM AND METHOD FOR CONTROLLING A IGNITION SEQUENCE OF AN ENGINE FOR REDUCING A VIBRATION DURING DEACTIVATION OF CYLINDERS OF THE MOROR - Google Patents

Abstract

A system according to the principles of the present disclosure includes a vibration prediction module and an ignition sequence module. The vibration prediction module predicts a vibration response of a vehicle based on an ignition sequence of an engine when a cylinder of the engine is deactivated. The ignition sequence module adjusts the ignition sequence of the engine based on the predicted vibrational response of the vehicle.

Description

REFER TO RELATED APPLICATIONS

This application claims the benefit of US Provisional Application No. 61 / 699,039, filed Sep. 10, 2012. The disclosure of the above application is incorporated herein by reference in its entirety.

This application is related to United States Patent Application No. 13 / 798,451, filed Mar. 13, 2013, No. 13 / 798,351, filed Mar. 13, 2013, No. 13 / 798,586, filed Jun. 13, 2013; No. 13 / 798,590 filed March 13, 2013, No. 13 / 798,536 filed on Mar. 13, 2013, No. 13 / 798,435, filed on Mar. 13, 2013, No. 13 / 798,471, filed Mar. 13, 2013, No. 13 / 798,737, filed Mar. 13, 2013, No. 13 / 798,701, filed Mar. 13, 2013, No. 13 / 799,129 No. 13 / 798,540, filed Mar. 13, 2013, No. 13 / 798,574, filed Mar. 13, 2013, No. 13 / 799,181, filed on Mar. 13, 2013 No. 13 / 799,116 filed on Mar. 13, 2013, No. 13 / 798,624, filed Mar. 13, 2013, No. 13 / 798,384, filed Mar. 13, 2013, No. 13 / 798,775, which issued on. March 13, 2013, and No. 13 / 798,400 filed March 13, 2013. The entire disclosures of the above applications are incorporated herein by reference.

TERRITORY

The present disclosure relates to systems and methods for controlling an ignition sequence of an engine to reduce vibration when cylinders of the engine are deactivated.

BACKGROUND

The background description provided herein is for the purpose of generally illustrating the context of the disclosure. Both the work of the present inventors, to the extent that it is described in this Background section, and aspects of the description, which are not otherwise considered to be prior art at the time of filing, are neither express nor implied Technique against the present disclosure approved.

Internal combustion engines combust an air and fuel mixture in cylinders to drive pistons, which generates drive torque. An air flow into the engine is regulated by means of a throttle. More specifically, the throttle adjusts a throttle area, which increases or decreases the flow of air into the engine. As the throttle area increases, the flow of air into the engine increases. A fuel control system adjusts the rate at which fuel is injected to provide a desired air / fuel mixture to the cylinders and / or to achieve a desired torque output. Increasing the amount of air and fuel delivered to the cylinders increases the torque output of the engine.

In spark ignition engines, a spark triggers the combustion of an air / fuel mixture that is delivered to the cylinders. In compression-ignition engines, the compression in the cylinders burns the air-fuel mixture delivered to the cylinders. Spark timing and airflow may be the primary mechanisms for adjusting the torque output of the spark-ignition engines, while fuel flow may be the primary mechanism for adjusting the torque output of the compression-ignition engines.

Under certain circumstances, one or more cylinders of an engine may be deactivated to reduce fuel consumption. For example, one or more cylinders may be deactivated when the engine may generate a requested amount of torque while the one or more cylinders are deactivated. The deactivation of a cylinder may include disabling the opening of intake and exhaust valves of the cylinder and disabling fueling of the cylinder.

SUMMARY

A system in accordance with the principles of the present disclosure includes a vibration prediction module and an ignition sequence module. The vibration prediction module says a vibration response of a vehicle based on an ignition sequence of an engine when a cylinder of the engine is deactivated. The ignition sequence module adjusts the ignition sequence of the engine based on the predicted vibration response of the vehicle.

Further fields of application of the present disclosure will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

1 FIG. 4 is a functional block diagram of an exemplary engine system according to the principles of the present disclosure; FIG.

2 FIG. 4 is a functional block diagram of an exemplary control system in accordance with the principles of the present disclosure; FIG.

3 FIG. 10 is a flowchart illustrating an example control method in accordance with the principles of the present disclosure; FIG. and

4 to 7 Graphics illustrating exemplary torque pulse signals and vehicle vibration response signals in accordance with the principles of the present disclosure.

DETAILED DESCRIPTION

When a cylinder deactivation system deactivates cylinders of an engine, an ignition sequence of the engine may be adjusted in a random or periodic manner to obtain a desired number of deactivated cylinders and / or to change which cylinders are deactivated. An ignition sequence can be adjusted without regard to the noise and vibration behavior of a vehicle. Therefore, a driver may experience an increase in noise and vibration of a vehicle when cylinders are deactivated. The number of vehicle applications incorporating the cylinder deactivation system may therefore be limited.

A control system and method in accordance with the principles of the present disclosure optimizes an ignition sequence of an engine when cylinders of the engine are deactivated to provide a balance between torque output, fuel economy, and vibration. Vibration responses are predicted for multiple firing sequence options that achieve a desired number of deactivated cylinders. One of the firing sequence options is selected based on the predicted vibration responses of the firing sequence options.

The vibration responses of an ignition sequence can be predicted by predicting vibration responses of torque pulses associated with cylinders in the firing order by determining the timing of the vibration responses and summing the vibration responses. The torque pulses may be estimated for firing cylinders and non-firing cylinders in an ignition sequence. Each torque pulse may correspond to a predetermined number (eg, two) of crankshaft revolutions. The vibrational response to each torque pulse may be predicted based on an impulse response function of the relationship between crankshaft torque and vehicle vibration.

The vibrational response of a future firing sequence may be affected by the vibrational responses of previous firing sequences. Therefore, the predicted vibrational response of a future firing sequence can be added to the vibratory responses of previous firing sequences to give an overall vibrational response. The total oscillation response of each firing sequence option may be expressed as a single value, such as a maximum peak-to-peak value that may be used to select one of the firing sequence options.

Now up 1 Referring to, an engine system includes 100 an engine 102 which burns an air / fuel mixture to produce a drive torque for a vehicle. The amount of drive torque generated by the motor 102 is based on a driver input from a driver input module 104 , Air is passing through an intake system 108 in the engine 102 admitted. The inlet system 108 includes an intake manifold 110 and a throttle valve 112 , The throttle valve 112 may include a butterfly valve with a rotatable blade. An engine control module (ECM) 114 controls a throttle actuator module 116 , which is the opening of the throttle valve 112 regulates to control the amount of air flowing into the intake manifold 110 is admitted.

Air from the intake manifold 110 gets into cylinder of the engine 102 admitted. For purposes of illustration, a single representative cylinder is shown 118 shown. The motor 102 however, it can have several cylinders. For example, the engine 102 2, 3, 4, 5, 6, 8, 10 and / or 12 cylinders. The ECM 114 may deactivate one or more of the cylinders, which may improve fuel economy under certain engine operating conditions.

The motor 102 can work using a four-stroke cycle. The four strokes include an intake stroke, a compression stroke, a combustion stroke and an exhaust stroke. During each revolution of a crankshaft (not shown), two of the four strokes occur in the cylinder 118 on. Therefore, two crankshaft revolutions are for the cylinder 118 necessary to go through all four bars.

During the intake stroke, air is released from the intake manifold 110 through an inlet valve 122 in the cylinder 118 sucked. The ECM 114 controls a fuel actuator module 124 that is a fuel injector 125 controls to regulate the amount of fuel supplied to the cylinder to achieve a desired air / fuel ratio. The fuel injector 125 can take the fuel directly into the cylinder 118 or in a mixing chamber, which is the cylinder 118 are assigned, inject. The fuel actuator module 124 can stop the injection of fuel into the cylinders, which are disabled.

The injected fuel mixes with air and generates an air / fuel mixture in the cylinder 118 , During the compression stroke, a piston (not shown) compresses in the cylinder 118 the air / fuel mixture. The motor 102 may be a compression-ignition engine, in which case the compression in the cylinder 118 the air / fuel mixture ignites. Alternatively, the engine 102 a spark ignition engine, in which case a spark actuator module 126 a spark plug 128 in the cylinder 118 based on a signal from the ECM 114 activated. The spark ignites the air / fuel mixture. The timing of the spark may be specified relative to the time that the piston is at its uppermost position, referred to as top dead center (TDC).

The spark actuator module 126 may be controlled by a timing signal specifying how far before or after TDC the spark is to be generated. Since the piston position is directly related to crankshaft rotation, the operation of the spark actuator module may 126 be synchronized with the crankshaft angle. In various implementations, the spark actuator module may 126 stop the delivery of the spark to the deactivated cylinders.

Generating the spark may be referred to as an ignition event. An ignition event causes combustion in a cylinder when an air / fuel mixture is delivered to the cylinder (eg, when the cylinder is active). The spark actuator module 126 may have the ability to vary the timing of the spark for each firing event. The spark actuator module 126 may even be able to vary the spark timing for a next firing event when the spark timing signal is changed between a last firing event and the next firing event. In various implementations, the engine may 102 have multiple cylinders, and the spark actuator module 126 may determine the spark timing relative to the TDC for all cylinders in the engine 102 vary by the same amount.

During the combustion stroke, combustion of the air / fuel mixture drives the piston down, thereby driving the crankshaft. As combustion of the air / fuel mixture drives the piston down, the piston moves from the TDC to its lowermost position, referred to as bottom dead center (BDC).

During the exhaust stroke, the piston begins to move up again from the BDC and drives the byproducts of combustion through an exhaust valve 130 out. The by-products of combustion are produced by means of an exhaust system 134 ejected from the vehicle.

The inlet valve 122 can through an intake camshaft 140 be controlled while the exhaust valve 130 through an exhaust camshaft 142 can be controlled. In various implementations, multiple intake camshafts (including the intake camshaft 140 ) several intake valves (including the intake valve 122 ) for the cylinder 118 and / or the intake valves (including the intake valve 122 ) several rows of cylinders (including the cylinder 118 ) Taxes. Similarly, multiple exhaust camshafts (including the exhaust camshaft 142 ) several exhaust valves for the cylinder 118 and / or the exhaust valves (including the exhaust valve 130 ) for several rows of cylinders (including the cylinder 118 ) Taxes.

The time to which the inlet valve 122 can be opened by an intake cam phaser 148 can be varied relative to the piston TDC. The time to which the exhaust valve 130 can be opened by an outlet cam phaser 150 can be varied relative to the piston TDC. The ECM can open the intake and exhaust valves 122 . 130 turn off the cylinder, which are disabled. A phaser actuator module 158 may be the intake cam phaser 148 and the exhaust cam phaser 150 based on signals from the ECM 114 Taxes. When implemented, a variable valve lift (not shown) may also be provided by the phaser actuator module 158 to be controlled.

The ECM 114 can the cylinder 118 Disable by using a valve actuator module 160 instructed to open the inlet valve 122 and / or the exhaust valve 130 to disable. The valve actuator module 160 controls an intake valve actuator 162 , the intake valve 122 opens and closes. The valve actuator module 160 controls an exhaust valve actuator 164 that the exhaust valve 130 opens and closes. According to one example, the valve actuators include 162 . 164 Solenoids that open the valves 122 . 130 Turn off cam followers by the camshafts 140 . 142 be decoupled. As another example, the valve actuators are 162 . 164 electromagnetic or electro-hydraulic actuators that control the stroke, timing and duration of the valves 122 . 130 independent of the camshafts 140 . 142 Taxes. In this example, the camshafts 140 . 142 , the cam phaser 148 . 150 and the phaser actuator module 158 be omitted.

The position of the crankshaft can be determined using a crankshaft position sensor (CKP sensor) 180 be measured. The temperature of the engine coolant may be determined using an engine coolant temperature (ECT) sensor. 182 be measured. The ECT sensor 182 can in the engine 102 or at other locations where the coolant circulates, such as in a radiator (not shown).

The pressure in the intake manifold 110 can be measured using a manifold absolute pressure (MAP) sensor 184 be measured. In various implementations, engine vacuum may be measured, which is the difference between the ambient air pressure and the pressure in the intake manifold 110 is. The mass flow rate of air entering the intake manifold 110 can flow using an air mass flow sensor (MAF sensor) 186 be measured. In various implementations, the MAF sensor 186 be arranged in a housing, which is also the throttle valve 112 includes.

The throttle actuator module 116 can the position of the throttle valve 112 using one or more throttle position sensors (TPS) 190 monitor. The ambient temperature of the air in the engine 102 can be admitted using an inlet air temperature sensor (IAT sensor) 192 be measured. The ECM 114 can use signals from the sensors to make control decisions for the engine system 100 hold true.

Now up 2 Referring to, an exemplary implementation of the ECM includes 114 a driver torque module 202 , an engine speed module 204 and a cylinder activation module 206 , The driver torque module 202 determines a driver torque request based on the driver input from the driver input module 104 , The driver input may be based on a position of an accelerator pedal. The driver input may also be based on cruise control, which may be an adaptive cruise control system that varies vehicle speed to maintain a predetermined following distance. The driver torque module 202 may store one or more maps of the accelerator pedal position to a desired torque, and may determine the driver torque request based on a selected one of the maps. The driver torque module 202 outputs the driver torque request.

The engine speed module 204 determines an engine speed. The engine speed module 204 can determine the engine speed based on an input from the CKP sensor 180 Will be received. The engine speed module 204 The engine speed may be based on an amount of crankshaft rotation between Detect teeth and their duration. The engine speed module 204 gives the engine speed.

The cylinder activation module 206 disables cylinder of the engine 102 based on the driver torque request. The cylinder activation module 206 can disable one or more cylinders when the engine 102 can satisfy the driver torque request while the cylinders are deactivated. The cylinder activation module 206 can reactivate the cylinders when the engine 102 can not satisfy the driver torque request while the cylinders are deactivated. The cylinder activation module 206 returns the number of deactivated cylinders and / or the number of active cylinders.

An ignition sequence module 208 determines an ignition sequence of the cylinders in the engine 102 , The ignition sequence module 208 can set and / or set the firing order after every engine cycle. Alternatively, the ignition sequence module 208 the firing sequence before each firing event in the engine 102 set and / or adjust. An engine cycle may equal 720 degrees of crankshaft rotation. An ignition sequence may include one or more cylinder events. For example, an ignition sequence may include 4, 5, 8 or 16 cylinder events. A cylinder event may refer to an ignition event and / or an increase in crank angle during which a spark is generated in a cylinder when the cylinder is active. The ignition sequence module 208 outputs the ignition sequence.

The ignition sequence module 208 may change the firing sequence from one engine cycle to the next engine cycle to change the number of active cylinders without changing the order in which the cylinders ignite. For example, for an 8-cylinder engine with a firing order of 1-8-7-2-6-5-4-3, an ignition sequence of 1-8-7-2-5-3 may be specified for one engine cycle, and it may be one Ignition sequence of 1-7-2-5-3 be specified for the next engine cycle. This reduces the number of active cylinders from 6 to 5.

The ignition sequence module 208 may change the number of active cylinders from one engine cycle to the next engine cycle based on instructions provided by the cylinder deactivation module 206 be received. The cylinder deactivation module 206 For example, the number of active cylinders may alternate between two integers to achieve an effective number of cylinders equal to the average between the two integers. For example, the cylinder deactivation module 206 the number of active cylinders alternates between 5 and 6, resulting in an effective number of cylinders of 5.5.

The ignition sequence module 208 can change the firing sequence from one engine cycle to the next engine cycle to change which cylinders are firing, and. thereby changing which cylinders are active without changing the number of active cylinders. For example, if three cylinders of the 8-cylinder engine described above are deactivated, an ignition sequence of 1-7-2-5-3 may be specified for one engine cycle, and an ignition sequence of 8-2-6-4 may be specified. 3 are specified for the next engine cycle. This deactivates the cylinders 1, 7 and 5 and reactivates the cylinders 8, 6 and 4.

A torque pulse module 210 estimates torque pulses from firing cylinders and non-firing cylinders. A vibration prediction module 212 predicts a vibrational response of the vehicle based on the firing sequence and torque pulses. The vibration prediction module 212 can predict the vibrational responses of multiple firing sequence options and output the predicted oscillations. The ignition sequence module 208 and / or the vibration prediction module 212 For example, ignition timing options may be determined based on the number of cylinders deactivated by the cylinder deactivation module 206 is issued.

The ignition sequence module 208 may select one of the firing sequence options based on the predicted oscillations. The ignition sequence module 208 can optimize the firing sequence to meet the driver torque request while maximizing fuel economy and minimizing vibration. The ignition sequence module 208 gives the ignition sequence to a fuel control module after optimization 214 , a spark control module 216 and a valve control module 218 out.

The torque pulse module 210 estimates the torque pulses based on engine operating conditions such as manifold pressure and engine speed. In various implementations, the torque pulse module may 210 the torque pulses based on the spark timing and the Estimate the timing of valves detected by the spark control module 216 or from the valve control module 218 can be received. When the torque pulses are estimated, the torque pulse module may 210 assume that despite the differences in location (eg, relative to the intake manifold 110 ) each firing cylinder generates the same torque pulse and each non-firing cylinder generates the same torque pulse.

The duration of each torque pulse may correspond to a duration of a thermodynamic cycle in a cylinder. For example, the duration of each torque pulse for a four-stroke engine may correspond to two crankshaft revolutions. The torque pulses may begin before an intake stroke when a piston is in a cylinder at TDC. Alternatively, the torque pulses may begin before an exhaust stroke when a piston is in a cylinder at BDC, which may correspond to the time that the intake and exhaust valves 122 . 130 be deactivated.

The vibration prediction module 212 may predict the vibrational response to each torque pulse in an ignition sequence based on a predetermined relationship between crankshaft torque and vehicle vibration. The predetermined relationship may be developed by laboratory testing and / or finite element analysis, and may be embodied in an equation and / or look-up table. In various implementations, the predetermined relationship may be embodied as an impulse response function, such as a unit impulse response function.

The vibration prediction module 212 can predict the vibrational response at one or more locations. For example, the vibration prediction module 212 predict the vibration response at a driver interface component, such as a driver's seat, a steering wheel, or a pedal. The vibration prediction module 212 can predict the vibrational response in one or more directions. For example, the vibration prediction module 212 predict the vibrational response in the longitudinal direction, the transverse direction and in vertical directions.

The vibration prediction module 212 can predict the vibrational response to each torque pulse in an ignition sequence by convolving each torque pulse with the unit impulse response function. The vibration prediction module 212 may predict the vibrational response of an ignition sequence by determining the time course of the vibrational response to each torque pulse in the firing sequence and by summing the portions of the vibrational responses that overlap in time. The vibration prediction module 212 can determine the time course of the vibration responses based on the crankshaft position and the engine speed.

The vibrational response of a future firing sequence may be affected by the vibrational responses of previous firing sequences because the vibrational responses may overlap in time. Therefore, the vibration prediction module 212 sum the vibrational response of the future firing sequence with the vibrational responses of previous firing sequences in the manner described above to obtain an overall vibrational response.

The total vibration response can be expressed in terms of a single value. For example, the total vibrational response may be expressed as a maximum peak-to-peak value of the total vibrational response. Additionally or alternatively, the total vibration response may be expressed as a ratio of the total vibration response to a predetermined vibration response. Various other vibration criteria can be used to quantify the overall vibrational response. The vibration prediction module 212 can output the ignition sequence options and the corresponding overall vibration responses.

The vibration prediction module 212 can predict the vibratory responses of the firing sequence options, and the firing sequence module 208 may select one of the firing sequence options at a first time. A first time period between the first time and a second time corresponding to the start of a cylinder event may be adjusted to enable the ECM 114 Cylinder activated or deactivated according to the selected ignition sequence option. For example, the first time period may be adjusted based on a period of time necessary to deactivate the intake and exhaust valves 122 . 130 is required.

The fuel control module 214 indicates the spark actuator module 124 on, fuel according to the firing sequence on cylinder of the engine 102 to deliver. The spark control module 216 indicates the spark actuator module 126 on, a spark according to the ignition sequence in cylinders of the engine 102 to create. The spark control module 216 may output a signal indicating which of the cylinders in the firing sequence is next. The spark control module 216 may be the spark timing of the firing cylinder to the torque pulse module 210 output. The valve control module 218 indicates the valve actuator module 160 on, the intake and exhaust valves of the engine 102 to open according to the ignition sequence. The valve control module 218 may be the timing of the valves of the firing cylinder to the torque pulse module 210 output.

In various implementations, the vibration prediction module 212 for each of the firing sequence options, predict vibration responses for multiple spark timings and multiple manifold pressures. The spark timings and manifold pressures may be selected from a predetermined range of spark timings and a predetermined range of manifold pressures, respectively. The vibration prediction module 212 may output the spark sequence options, spark timings, manifold pressures, and vibration responses that correspond to each combination of spark sequence option, spark timing, and manifold pressure.

The ignition sequence module 208 can optimize the spark sequence, spark timing, and manifold pressure to meet the driver torque request while maximizing fuel economy and minimizing vibration. The ignition sequence module 208 can output the ignition sequence, the spark timing, and the manifold pressure after optimization. The spark control module 216 then can set the optimized spark timing to the spark actuator module 126 output. Additionally, a throttle control module (not shown) and the valve control module 218 Set a throttle area or the timing of the valves based on the optimized ignition sequence and / or the optimized manifold pressure. The throttle control module may apply the throttle area to the throttle actuator module 116 output. In addition, the fuel control module 214 control the injection amount and / or the injection timing based on the optimized firing sequence.

In various implementations, an optimization module (not shown) may optimize the ignition sequence, the spark timing, and the manifold pressure to meet the driver torque request while maximizing fuel economy. The optimization module may output the ignition sequence, the spark timing, and the manifold pressure after optimization. The optimizer can do the optimization and the results instead of the firing sequence module 208 output. The optimization module may include the vibration responses corresponding to each combination of spark sequence option, spark timing, and manifold pressure from the vibration prediction module 212 receive. The optimization module may receive the torque output corresponding to each combination and the fuel economy corresponding to each combination from a torque estimation module (not shown) and a fuel economy module (not shown), respectively. The fuel economy module may estimate the fuel economy of the vehicle for each combination of ignition sequence option, spark timing, and manifold pressure. The torque estimation module may determine the torque output of the engine 102 for each combination of ignition sequence option, spark timing and manifold pressure.

Now up 3 Referring to, starts at 302 a method for controlling an ignition sequence of an engine to reduce vibration when cylinders of the engine are deactivated. at 304 the method determines ignition sequence options. The method may determine the firing sequence options based on the number of cylinders that are deactivated.

at 306 the method estimates torque pulses from igniting and non-igniting cylinders. The method may estimate the torque pulses based on engine operating conditions, such as manifold pressure, engine speed, spark timing, and / or valve timing. If the torque pulses are estimated, the method may assume that each firing cylinder generates the same torque pulse and that each non-firing cylinder generates the same torque pulse. However, the method can not use this assumption if greater accuracy is desired.

The duration of each torque pulse may correspond to a duration of a thermodynamic cycle in a cylinder. For example, the duration of each torque pulse for a four-stroke engine may correspond to two crankshaft revolutions. The torque pulses may begin before an intake stroke when a piston in a cylinder is at the TDC. Alternatively, the torque pulses may begin before an exhaust stroke when a piston in a cylinder is at the BDC.

at 308 For example, the method predicts the vibrational response of a vehicle for each torque pulse in an ignition sequence option. The method may predict the vibration response based on a predetermined relationship between the crankshaft torque and the vibration response. The predetermined relationship may be developed by laboratory testing and / or finite element analysis, and may be embodied in an equation and / or look-up table. In various implementations, the predetermined relationship may be embodied as an impulse response function, such as a unit impulse response function.

The method may predict the vibrational response at one or more locations in the vehicle. For example, the method may predict the vibration response at a driver interface component, such as a seat, a pedal, or a steering wheel. The method can predict the vibrational response in one or more directions. For example, the method may predict the vibrational response in the longitudinal direction, the transverse direction, and / or in vertical directions.

The method may predict the vibrational response to each torque pulse in a first firing sequence option by convolving each torque pulse with the unit impulse response function. In some cases, a torque pulse and the unit response function may be folded once, and the resulting vibration response stored for repeated use. If the engine operating conditions are the same as or similar to those that yield the torque pulse, then the stored vibration response may then be retrieved from memory instead of estimating a torque pulse and then predicting a vibration response to the torque pulse.

at 310 the method determines the time course of the vibration response response for each torque pulse in an ignition sequence option. The method may determine the time course of the vibration responses based on the crankshaft position and the engine speed. at 312 The method sums the vibration responses for the torque pulses in an ignition sequence option to obtain a vibration response for the ignition sequence option. The method adds the vibrational response of the firing sequence option to the vibratory responses of previous firing sequences to obtain an overall vibrational response associated with the firing sequence option.

The total vibration response can be expressed in terms of a single value. For example, the total vibrational response may be expressed as a maximum peak-to-peak value of the total vibrational response. Additionally or alternatively, the total vibration response may be expressed as a ratio of the total vibration response to a predetermined vibration response. Various other vibration criteria can be used to quantify the overall vibrational response.

at 314 the method determines whether the vibrational responses for each firing sequence option are predicted. If the vibrational responses are predicted for each firing sequence option, the method continues 316 continued. Otherwise, the procedure continues 310 continued. at 316 The method selects one of the firing sequence options based on the predicted vibration responses. The method may optimize the firing sequence to maximize fuel economy and minimize vibration while meeting a torque request.

Now up 4 Referring to FIG 402 an example of a unit impulse response of a vehicle to a crankshaft torque is shown. The unit impulse response 402 is relative to the x-axis 404 and a y-axis 406 applied. The x-axis 404 represents the time in seconds. The y-axis 406 represents the acceleration in meters per second squared (m / s ² ).

The unit impulse response 402 is determined by eigenvibration modes of the vehicle. The unit impulse response 402 can be obtained by finite element analysis or by physical measurements. The unit impulse response 402 varies for different measuring points on the vehicle body and with the direction of the measured vibration.

Now up 5 Referring to FIG 502 an example of a firing pulse of a firing cylinder in an engine operating at 1250 revolutions per minute (RPM) and at 504 an example of a torque pulse of a non-igniting cylinder is shown in the engine. The torque pulses 502 . 504 are related to an x-axis 506 and a y-axis 508 applied. The x-axis 506 represents the time in seconds. The y-axis 508 represents the torque in Newton meters (Nm). The torque pulses 502 . 504 take about 0.096 seconds. However, as discussed above, the duration of the torque pulses may be based on a predetermined number of crankshaft rotations (eg, two), and may therefore depend on engine speed.

Now up 6 Referring to FIG. 1, an example of vibration responses of a vehicle is represented by the unit impulse response 402 are characterized at 602 and 604 shown. The vibration responses 602 and 604 are each by the torque pulses 502 . 504 caused. The vibration responses 602 . 604 are related to an x-axis 606 and a y-axis 608 applied. The x-axis 606 represents the time in seconds. The y-axis 608 represents the acceleration in m / s ² . The vibration responses 602 . 604 last longer than a second as it is in 6 is shown, although the torque pulses 502 . 504 take only about 0.096 seconds.

Now up 7 Referring to FIG 702 an example of a vibration response of a vehicle due to 160 torque pulses in a V8 engine operating at 1250 RPM. The vibration response 702 is relative to an x-axis 704 and a y-axis 706 applied. The x-axis 704 represents the time in seconds. The y-axis 706 represents the acceleration in m / s ² .

The firing pattern (ie the firing sequence) of the engine is randomly selected with, on average, four of the eight cylinders firing every two revolutions. The torque pulses occur during 40 crankshaft revolutions between 0 seconds and 1.92 seconds. The vibration response 702 begins to drop to zero when the torque pulses stop.

7 represents the adverse effect of randomly selecting an ignition sequence. The amplitude of the vibration response 702 is greater than the amplitude of a vibration response caused by a uniformly-firing V8 engine. The frequency of the vibration response 702 is more irregular than the frequency of a vibrational response caused by a steady-firing V8 engine.

Table 1, given below, illustrates pre-selected firing patterns of a V8 engine as well as future firing pattern options and their predicted peak vibration levels in accordance with the principles of the present disclosure. Each firing pattern corresponds to two crankshaft revolutions (eg, revolution 1-2). In each firing pattern, "1" represents a firing (ie, active) cylinder, and "0" represents a non-firing cylinder. The peak vibration level is a ratio of a predicted vibration response to a predetermined vibration response. Table 1

Ignition patterns alternate between five active cylinders and six active cylinders to achieve an effective number of cylinders of 5.5. The ignition pattern options include six active cylinders because the firing pattern of the last revolution (i.e., revolutions 9-10) contains five active cylinders.

An ignition pattern option may include one or more cylinder events. The number of cylinder events in a firing pattern option may be predetermined to reduce the number of decisions taken in a given period of time to make prior determinations to use the vibration response of certain firing sequences and / or to ensure smooth torque delivery. In Table 1, the ignition pattern options each include eight cylinder events with six firing events.

The vibrational responses of the previously selected firing patterns are predicted by convolution and summation in the manner described above to obtain a current vibrational response. The vibrational responses of the future firing pattern options are predicted and summed with the current vibrational response to obtain an overall vibrational response. Depending on the phase and amplitude of the predicted vibrational response relative to the current vibrational response, the predicted vibrational response in different frequency ranges may constructively or destructively interfere with the current vibrational response.

The total vibration response predicted for each ignition pattern option is divided by a predetermined vibration response to obtain the peak vibration levels. The predetermined vibration response may be a specification. Therefore, a peak vibration level may satisfy the specification when the peak vibration level is less than or equal to 1.00.

In Table 1, the vibration pattern option 11011101 gives a peak vibration level of 0.55, which is the lowest peak vibration level of those listed in Table 1. However, this ignition pattern option may not be selected for the next engine cycle due to performance factors other than vehicle vibration response, such as torque delivery.

The foregoing description is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure may be implemented in a variety of forms. Therefore, while this disclosure has specific examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. For the sake of clarity, the same reference numerals will be used in the drawings to identify similar elements. As used herein, formulation A, B and / or C should be construed to mean a logical (A or B or C) using a non-exclusive logical-oder. It is understood that one or more steps within a method may be performed in a different order (or concurrently) without altering the principles of the present disclosure.

As used herein, the term module may refer to an application specific integrated circuit (ASIC); an electronic circuit; a circuit of the circuit logic; a field programmable gate array (FPGA); a processor (shared, dedicated, or group) that executes a code; other suitable hardware components that provide the described functionality; or a combination of some or all of the above objects, such as in a one-chip system, be part of, or include. The term module may include memory (shared, dedicated, or group) that stores a code that is executed by the processor.

The term code as used above may include software, firmware, and / or microcode, and may refer to programs, routines, functions, classes, and / or objects. The term shared as used above means that a portion of the code or the entire code of multiple modules can be executed using a single (shared) processor. In addition, part or all of the code of several modules may be stored by a single (shared) memory. The term group as used above means that part or all of the code of a single module can be executed using a group of processors. Additionally, part of the code or code of a single module may be stored using a group of memories.

The apparatus and methods described herein may be implemented by one or more computer programs executed by one or more processors. The computer programs comprise processor-executable instructions stored on a non-transitory, accessible, computer-readable medium. The computer programs may also include stored data. Non-limiting examples of the non-transitory, accessible, computer-readable medium include nonvolatile memory, magnetic memory, and optical memory.

Claims (10)

A method comprising: a vibration response of a vehicle is predicted based on an ignition sequence of an engine when a cylinder of the engine is deactivated; and the ignition sequence of the engine is adjusted based on the predicted vibration response of the vehicle. The method of claim 1, further comprising predicting the vibration response based on torque pulses from firing cylinders and non-firing cylinders in the firing sequence. The method of claim 2, further comprising: the oscillation response is predicted for each torque pulse; the time course of the oscillation response is determined for each torque pulse; and Suffixing portions of the vibration responses that overlap in time to obtain the vibrational response of the firing sequence. The method of claim 3, further comprising estimating the torque pulses based on a pressure in an intake manifold of the engine and an engine speed. The method of claim 2, further comprising predicting the vibrational response of each torque pulse based on a predetermined relationship between crankshaft torque and vehicle vibration. The method of claim 5, wherein the predetermined relationship comprises an impulse response function. The method of claim 1, further comprising: the vibration response of the vehicle is predicted according to a plurality of ignition sequence options; and selecting one of the ignition sequence options based on the predicted vibration response of the vehicle. The method of claim 7, further comprising determining the ignition sequence options based on a number of active cylinders that meets a driver torque request. The method of claim 7, further comprising: a first oscillation response is determined for a previous firing sequence; a second vibrational response is predicted for each of the firing sequence options; determining an overall vibrational response for each of the firing sequence options based on the first vibrational response and the corresponding second vibrational response; and one of the ignition sequence options is selected based on the total vibration response. The method of claim 9, further comprising determining total vibration response for each of the firing sequence options by: the time course of the first oscillation response and the corresponding second oscillation response is determined; and Proportions of the first vibrational response and the corresponding second vibrational response that overlap in time are summed.

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